Most gun research related to intimate partner violence focuses on fatalities, but Susan B. Sorenson, a professor of social policy in the School of Social Policy & Practice and director of the Evelyn Jacobs Ortner Center on Family Violence, took a different approach. Instead of researching fatalities, she looked at what happens when weapons enter into intimate relationships but don’t result in death.

“This is really about women’s lives,” says Sorenson, who co-authored a recent paper about the topic in the journal Trauma, Violence & Abuse with former Penn undergrad Rebecca Schut. “It’s about how people live their lives, not just whether they survive.”

Sorenson and Schut decided to conduct a systematic review of the literature to date on the subject, which enabled them to better understand nonfatal gun use in intimate partner violence. They learned that there is not a whole lot of information, whittling down thousands of articles to just 10 that matched their criteria.

Though rare compared to many diseases, 3.5 percent of women in the United States reported experiencing nonfatal gun use in intimate partner violence. In 2016, that’s equivalent to 4.5 million women having their partners threaten them with a gun. Another 1 million have been shot or shot at by an intimate partner.

“You could just pull a gun on an intimate partner once and that will change the nature of the relationship,” Sorenson says. “If it happened once, when might it happen again?”

Broadly speaking, she’s referring to a notion called coercive control, what the researchers describe in the paper as “an intentional pattern of repeated behavior by an abuser to control, denigrate, intimidate, monitor, and restrict an intimate partner.”

“It’s essentially what makes ongoing physical and sexual abuse possible,” Sorenson says. “It creates an environment and a climate of fear and intimidation.”

It’s a mental power play that happens over time. And, she adds, hostile displays—placing a handgun on a table in the midst of an argument, for instance—and actually threatening a partner can have similar negative outcomes. When faced with a gun, regardless of whether it is fired, a woman may decide to acquiesce.

Additional research in this field for Sorenson focuses not just on whether a gun gets used, but how. She recently began comparing domestic violence calls with and without a weapon, and evaluating the difference between weapon types (e.g., guns versus body parts versus an external weapon like a brick or bat).

“One might assume that if a gun was used, the woman is more likely to be injured. But you could also argue the opposite, that if a gun is used, she might be less likely to resist,” Sorenson says. “This research is shedding light on those issues.”